Rotating seals for cell processing systems

ABSTRACT

The invention provides an improved rotating seal apparatus including a plurality of concentrically spaced annular rotating seals. The invention also provides a rotating seal apparatus including a pressurized annular chamber surrounding an annular rotating seal.

RELATED APPLICATION

[0001] This application claims the benefit under Title 35, U.S.C.§119(e) of pending U.S. Provisional Application Serial No. 60/047,213,filed May 20, 1997, entitled “Cell Processing System”, incorporatedherein by reference. This application is also related to co-pending U.S.Patent Applications entitled: “Apparatus and Method for Expressing FluidMaterials” (Attorney Docket Z0090/7013); “Fluid Management Systems”(Attorney Docket Z0090/7014); “Optical Sensors for Cell ProcessingSystems” (Attorney Docket Z0090/7015); and “Cell Processing Systems”(Attorney Docket Z0090/7016), all of which are incorporated byreference.

FIELD OF THE INVENTION

[0002] The invention relates to rotating seals for centrifugal devicesuseful, inter alia, in cell processing or cell washing applications.

BACKGROUND OF THE INVENTION

[0003] Generally, cell processing requires steps in which cells or cellelements are separated from a liquid phase. This separation is typicallyaccomplished by centrifugation. The sterility of the cells beingprocessed is protected by the incorporation of a dynamic seal betweenrotatable and stationary centrifuge elements, referred to as a “rotatingseal”. In addition to deterring the entrance of microbes into thesterile environment of the processing apparatus and the biologicalmaterials contained therein, a rotating seal ideally minimizes theleakage of air and frictional heating and is capable of tolerating mildto moderate misalignment and vibration.

[0004] A number of designs for rotating seals have been developed. Forexample, U.S. Pat. No. 3,489,145 by Judson et al. discloses a lowerrotating element that forms a seal with an upper stationary element, andthat has a central bore extending throughout. U.S. Pat. Nos. 3,409,203and 3,565,330 by Latham disclose rotating seals formed from a stationaryrigid low-friction element in contact with a moving rigid element and anelastomeric element which provides a resilient static seal as well as amodest closing force between the seal surfaces. U.S. Pat. No. 3,801,142by Jones et al. relates to a pair of elements having confronting annularfluid-tight sealing surfaces maintained in a rotatable but fluid-tightrelationship by axial compression of a length of elastic tubing. In the“B.T. Bowl” marketed by Bellco (Mirandola, Italy), a rotating seal isformed between a ceramic ring element attached to rotatable elements ofa centrifuge and a fixed graphite ring attached to stationary centrifugeelements; an elastomeric diaphragm is attached at one end to an adapterring for the graphite ring and at the other end to a stationary part ofthe centrifuge. U.S. Pat. Nos. 4,300,717 and 5,045,048 by Latham, Jr.relate to a rotating seal which has been modified by the incorporationof recessed areas contiguous with “sealed” regions; the recessed areasare in communication with the external environment and are used toentrap and expel extraneous particles which may form duringcentrifugation.

[0005] In the field of centrifugal cell washing, two technologiescurrently dominate the state of the art, as exemplified by the Cobe 2991and the Haemonetics Model 115 cell washers. Both systems employ a set ofrotating seals to contain the fluids in the disposable rotatingcontainers. These seals have been classified by the FDA as “open”devices for the purpose of washing red blood cells, in that the sealshave not yet been validated as having the ability to satisfactorilyprevent biological contamination of the sterile interior under allrunning and handling conditions. According to the American Associationof Blood Banks (“AABB”) standards, “when glycerolizing ordeglycerolizing involves entering the container, the system isconsidered ‘open’ and the resulting suspension of deglycerolized cellscan be stored for only 24 hours at 1-6 degrees Centigrade.” This 24-hourstorage shelf life after deglycerolization, and other factors (includingcost), make the foregoing systems less useful for routine inventorymanagement and relegate them primarily to specialty uses such as storingrare blood types, autologous donations, or battlefield applications forthe Navy.

[0006] None of the foregoing rotating seals provides a seal whichpermits the storage of processed biological materials such as red bloodcells for extended period of time. The foregoing seals do not provideadequate protection from the contamination of processed biologicalmaterials by microbial contaminants.

SUMMARY OF THE INVENTION

[0007] The invention provides an improved rotating seal which providesenhanced anticontamination properties for use in particular incentrifugal devices for processing biological materials. The seal of theinvention comprises at least two concentrically spaced rotating seals,wherein the annular space between the seals forms at least one sterilechamber. In the event of a leak in one of the concentrically spacedrotating seals, the additional seal or seals act to maintain the sterileenvironment of the cell processing system by reducing or preventingmicrobial contamination. In addition, the sterile annular chamber can bepressurized with a sterile supply of gas as a second means of reducingor preventing microbial contamination. The pressurized chamber acts as abarrier to prevent microbes from migrating into the interior of the cellprocessing system across a leaky seal. The pressurized chamber also actsas a barrier to reduce or prevent the migration of fluids or particulatematter from the interior of the cell processing system across the aleaky seal.

[0008] According to one aspect of the invention, an improved cellprocessing system is provided, the improvement comprising a plurality ofannular rotating seals between rotating and non-rotating portions of thecell processing system. The plurality of annular rotating seals defineat least one annular space between the annular rotating seals. The atleast one annular space is constructed and arranged for receivingpressurized gas. In some embodiments, the plurality of annular rotatingseals includes a plurality of sealing members defining annular sealingsurfaces which form a plurality of concentrically spaced annularrotating seals, the annular rotating seals defining at least one annularspace. At least one of the sealing members defines a channel in anon-sealing surface, which channel is in gaseous communication with theat least one annular space. Preferably the at least one annular space ispressurized with gas. In certain preferred embodiments, the annularsealing surfaces are substantially planar. In other embodiments, theapparatus also includes a body defining a gas port, wherein the gas portis in gaseous communication with the channel. The apparatus also caninclude a pressure sensor in communication with the gas port formonitoring the gas pressure in the annular space.

[0009] According to another aspect of the invention, a seal apparatus isprovided. The seal includes plurality of annular seal members. A firstannular rotating seal member includes a sealing face which defines aplurality of concentrically spaced annular sealing surfaces, and anaxial opening. A second annular rotating seal member has a sealing facewhich defines at least one annular sealing surface, and an axialopening. The first annular rotating seal member and the second annularrotating seal member are axially aligned and the annular sealingsurfaces are placed in contact to form a plurality of spaced apartseals. Preferably the annular sealing surfaces are substantially planar.In certain embodiments, the sealing face of the first sealing elementfurther defines an annular space between the annular sealing faces. Theannular sealing surfaces can be biased together by a bias element, whichpreferably is an elastomeric spring element. The annular sealingsurfaces are preferably formed of a material selected from the groupconsisting of ceramics, carbon phenolic and equivalent carbon compositematerials; more preferably, all annular sealing surfaces are formed ofceramic materials. In other embodiments, at least one of the non-sealingfaces of the first annular rotating seal member and the second annularrotating seal member define a channel in gaseous communication with theannular space.

[0010] The seal apparatus also can include a body which includes a firstport disposed in the axial openings of the first and second annularrotating seal members. Preferably at least one of the non-sealing facesof the first annular rotating seal member and the second annularrotating seal member define a channel in gaseous communication with theannular space, wherein the body includes a gas port in communicationwith the channel. The seal apparatus also includes in some embodiments abase having an axial opening and a processing container having a topdefining an axial opening. The base is mounted in axial alignment on thetop of the processing container, and the second annular rotating sealmember mounted in axial alignment on the top surface of the base. Thusassembled, the first port of the seal apparatus is in fluidcommunication with the interior of the processing container. Preferablythe first port extends through the axial openings of the first andsecond annular rotating seal members and the base. The body also caninclude a fluid port in fluid communication with the space defined bythe first port, the first and second annular rotating seal members andthe axial opening of the base. In additional embodiment, the sealapparatus includes an outer shield defining a space between the outershield and the body, the base and the first and second annular rotatingseal members. Preferably the outer shield comprises a shield top, ashield bottom and a shield clamp, wherein the shield top is releasablymounted on the shield bottom, and wherein shield bottom and shield clamphave overlapping flanges which form a serpentine seal. In certainembodiments, the diameter of the shield bottom is smaller than thediameter of the shield clamp, the shield bottom has outwardly directedflange, and the shield clamp has an overlapping inwardly directedflange.

[0011] The seal apparatus also includes in certain embodiments anelastomeric spring element disposed between the shield top and the body,wherein the clamp is movable between a first position and a secondposition wherein the shield clamp is engaged with the base, wherein thespring element is compressed when the shield clamp is in the secondposition.

[0012] According to yet another aspect of the invention, a method forsealing a rotating processing container which rotates in a processingsystem is provided. The method includes providing a stationary sealmember mounted on a processing system, the stationary seal having aplurality of circumferentially spaced annular sealing elements. Themethod also includes providing a rotating seal member mounted on therotating processing container, the rotating seal member at least oneannular sealing element. The sealing elements of the stationary sealmember and the at least one sealing element of the rotating sealingmember are contacted to form a rotating seal between the rotatingprocessing container and the processing system.

[0013] According to another aspect of the invention, a method forsealing a rotating processing container is provided. The method includesproviding a plurality of annular seals between the rotating processingcontainer and a stationary portion of a processing system, wherein theplurality of annular seals define an annular space. The annular space ispressurized to provide an improved seal for the rotating processingcontainer.

[0014] According to still another aspect of the invention, a method forheating or cooling a sample during transport of the sample into or outof a rotating processing container is provided. A seal apparatusincluding a rotating seal and a port for transport of a sample to therotating processing container is provided, wherein the seal and the portdefine a space in contact with the port. The space between the seal andthe port is filled with a material having a temperature which is at orbelow the temperature of the sample for cooling the sample, or amaterial having a temperature which is at or above the temperature ofthe sample for heating the sample. In preferred embodiments, the methodprovides for cooling of the sample by filling the space with wastematerials generated by the processing methods, the waste materials beingat or below room temperature. In certain embodiments the method providescooling of the seal material during the transport of processing fluidsinto or out of the rotating processing container. The method includesproviding a seal having an annular-shaped inlet/outlet port in fluidcommunication with the processing fluids, and filling the annular spacedwith fluids that are cooler that the seal materials

[0015] In yet another aspect of the invention, a spring is provided. Thespring includes a hollow elastomeric cylinder having bowed sideportions. The spring can be constructed of a certain height, width,thickness and side portion arc to provide a constant biasing force uponcompression of the spring. The compression of the spring concurrentlychanges the height, width and arc. In certain embodiments, the springincludes an elastomeric material of relatively thin cross-section whichhas a geometry that delivers a relatively constant force over a widerange of deflection values. Preferably the spring has a cross-sectionalshape that includes bowed side walls.

[0016] Thus the invention provides a seal apparatus including aplurality of annular seals, and/or a seal apparatus including at leastone annular seal and a pressurized annular space concentrically spacedapart from the annular seal. Methods of using the seal apparatuses forsealing rotating containers also are provided.

[0017] These and other aspects of the invention will be described infurther detail in connection with the detailed description of theinvention.

BRIEF DESCRIPTION OF THE FIGURES

[0018]FIG. 1 is a perspective view of an interactive cell processingsystem.

[0019]FIG. 2 is a conceptual flow diagram displaying operation of aninteractive cell processing system.

[0020]FIG. 3 is a block diagram of the interactive cell processingsystem of FIG. 1.

[0021]FIG. 4 is a cross-section view of a centrifuge bucket and chuckwhich depicts the mounting of the rotating seal assembly in thecentrifuge.

[0022]FIG. 5 is a perspective view of the exterior of the rotating sealapparatus.

[0023]FIG. 6 is a cross-section view of the rotating seal apparatus.

[0024]FIG. 7 is an exploded cross-section view of the rotating sealapparatus.

[0025]FIG. 8 is an exploded top perspective view of the rotating sealapparatus and processing container.

[0026]FIG. 9 is an exploded bottom perspective view of the rotating sealapparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The preferred embodiments of the invention are described withreference to the drawings. Referring to FIGS. 1 and 3, an interactivecell processing system 10 includes a cell module 12, a supply module 20,a fluid distribution module 40, a processing module 60, a collectionmodule 70 (not shown in FIG. 1) and a control module 80. These modulesare operatively interconnected for processing biological cells in asterile environment. Cell module 12 is constructed for a short term orlong term storage of biological cells for processing. Supply module 20includes several containers for storing different process chemicalsincluding saline, or other fluids used for washing the processed cellsand also includes sterile air. The containers are connected to fluiddistribution module 40 by a set of conduits. Fluid distribution module40 includes several valves and sensors for dispensing controlled amountsof the process chemicals from supply module 20 to processing module 60and for dispensing a known amount of the biological cells from cellmodule 12 to processing module 60. Furthermore, fluid distributionmodule 40 is constructed to direct the process waste from processingmodule 60 to a waste container 72 and the processed cells to a cellstorage container 74, both of which are located in collection module 70,while maintaining the purity and sterility of the cells. Control module80 directs the entire process according to a selected algorithm.

[0028] In general, the operation of cell processing system 10 is shownin FIG. 2. Control module 80 executes a processing algorithm selectedinitially (98). Control module 80 includes a logic controller thatreceives real-time data from several in-line sensors arranged in aprocessing loop. A mass sensor (or a volume sensor) measures an initialamount of the provided biological cells (94) and sends the data tocontrol module 80. Control module 80 controls the amount of cellsdispensed to processing module 60 in accordance with the processingalgorithm. Based on the provided amount of the biological cells, controlmodule 80 also calculates the individual doses of the process chemicals(100) and directs a set of control valves to dispense the chemicals(102) in a selected order to processing module 60, again in accordancewith the processing algorithm.

[0029] Control module 80 executes iteratively the processing algorithm.Control module 80 receives data from the individual sensors (e.g., aweight sensor, a volume sensor, a temperature sensor, an optical sensor,a resistance or capacitance sensor, a flow sensor, a pressure sensor oranother sensor arranged to monitor the transferred matter in a liquid,gaseous or solid state). After dispensing the selected amount of one orseveral processing chemicals to processing module 60, control module 80regulates the temperature and the time of processing and directs theprocessing module to agitate, mix or otherwise treat the cells with theprocess chemicals. Depending on the processing algorithm, control module80 may manage one or several processing cycles. At the end of eachcycle, processing module 60 may separate the processed cells fromintermediate products and from the process waste. During the separationprocess, fluid distribution module 40 detects the fluid component beingexpressed from processing module 60 and directs the separated componentsto different containers for disposal (110) or for storage (112). Eachprocessing cycle may use a different processing chemical and differentprocessing conditions. Cell processing system 10 can also processdifferent types of cells at the same time or sequentially. Furthermore,cell processing system 10 may also partially process biological cellsand then store them in cell storage container 74 (shown in FIG. 3),which may include a temperature control system. The processed cells maybe later automatically dispensed from cell storage container 74 andprocessed using another processing algorithm. The processed cells mayalso be grown in culture prior to another use.

[0030] Based on the starting weight of the biological cells, thecontroller calculates the dosage of the processing chemicals. Supplymodule 20 includes a weight sensor 29 for providing the weight of eachprocess chemical to the controller. During the process, the controllerconfirms that correct amount of each process chemical has beentransferred by measuring the change in the weight of the processchemical stored in supply module 20 and the initial weight of thechemical. The process chemicals in a fluid state are pumped through a0.2 micron filter to assure sterility. A pressure transducer is mountedup-stream from the filter. If the fluids being pumped through the filterhave a variable viscosity, the controller will adjust the pumping speedto yield a constant pressure drop across the filter membrane.

[0031] Processing module 60 is designed to assure identical processingconditions (e.g., pressure, temperature, mixing, processing time orother) for large and small amounts of the biological cells provided forprocessing. For this purpose, processing module 60 includes a processingchamber that has a variable volume design. Depending on the volume ofthe processed cells and other processing chemicals transferred into theprocessing chamber, the controller changes the chamber volume. Thevolume change is achieved by a movable wall that may be a membrane.Processing module 60 includes another pressure sensor for measuring thepressure inside the processing chamber and also includes a temperaturesensor for measuring the temperature inside the processing chamber.Based on the data from the temperature sensor, a heat transfer systemcan provide or remove heat from the processing chamber.

[0032] Cell processing system 10 may process or separate cells and/orcell elements from different liquids or solids. Such cells and cellelements include, but are not limited to, erythrocytes (i.e., red bloodcells); leukocytes (i.e., white blood cells, including lymphocytes,granulocytes, and monocytes); blood cell progenitors (e.g., primitivestem cells, burst forming units, reticulocytes, megakaryocytes, etc.);cell fragments (e.g., platelets, subcellular elements such as nuclei,debris, etc.); epithelial cells; endothelial cells; mesothelial cells;cells of normal tissues (e.g., liver cells, kidney cells, bladder cells,lung cells, pancreatic cells, embryonic cells, fetal cells, etc.); cellsof abnormal tissues (e.g., malignant cells), and so forth.

[0033] Referring again to FIG. 3, in one preferred embodiment of thecell processing system, cell module 12 includes a weight sensor 14arranged to weigh red blood cells provided in a bag 16. Tubing 17connects bag 16 to a leuko filter 18 and to fluid distribution module40. Supply module 20 includes a bag 21 with enzyme A1/B, a bag 22 withenzyme A2, a bag 23 with 140 Molar potassium phosphate dibasic (DPP), abag 24 with polyethylene glycol (PEG), a bag 25 with storage solution,and a bag 26 with phosphate citrate isotonic (PCI). Each bag isconnected by tubing 28 to fluid distribution module 40. Weight sensor 29is constructed to weigh any of the above-mentioned fluids located insupply module 20. Supply module 20 also includes a compressor 30connected via a filter 31 and a check valve 32 to air reservoir 33,which stores sterile air used for cell processing. Pressure switch andsensor 34 is in communication with air tubing 36, which delivers sterileair to an air filter located in fluid distribution module 40. Aregulator 37, connected to a solenoid valve 36, regulates the airpressure provided to fluid distribution module 40 and to processingmodule 60. Fluid distribution module 40 includes a peristaltic pump 42,and twelve plunger valves 43, 44, . . . , and 54 connected to a set ofconduits for distributing the process chemicals and the cells during theautomated process. The logic controller can close or open anycombination of the twelve valves to redirect the fluid flowing insidethe conduits. A pressure sensor 55 measures the fluid pressure duringthe process, and a optical detector 58 monitors the fluid to and fromprocessing module 60. Processing module 60 includes a centrifuge 62 andan expresser system 64. An infra-red (IR) temperature sensor 68 monitorsthe temperature of the process chemicals or the cells located insidecentrifuge 62. Collection module 70 includes a waste bag 72, a salinesolution bag 73, and a product bag 74. Collection module 70 alsoincludes a weight sensor 76 connected to product bag 76 and arranged toweigh the processed red blood cells.

[0034] The controller controls the volume of the processing chamber ofcentrifuge 62 to assure identical processing conditions for large orsmall amounts of the red blood cells. The processing chamber includes amembrane for containing expresser fluid. For small volumes, expressersystem 64 pumps expresser fluid into the chamber until the pressuretransducer at the chamber signals a full condition. This pre-fillingstep assures that different amounts of red blood cells are subjected tothe same accumulated centrifugal force and mechanical stresses due topacking. Otherwise, smaller amounts would spin longer and pack harder asthe expresser fluid fills the processing chamber during the expressionstep.

[0035] During the process, the controller receives input from IRtemperature sensor 66, which measures the temperature of the RBCs. Ifthe temperature is less than the set point, expresser of system 64increases the temperature of the expresser fluid. Conversely, if thetemperature is greater than the set point, expresser of system 64decreases the temperature of the expresser fluid. A control loopcontinuously monitors the temperature of the processed cells.

[0036] Processing module 60 also includes a second pressure transducerthat monitors the pressure of the sterile air on the rotating seal. Ifthe seal is working, this pressure only fluctuates slightly betweenestablished limits. If the pressure drops below the establishedthreshold, a warning condition is initiated that calls for a check ofthe rotating seal as well as other possible causes of failure.

[0037] Expresser fluid system 64 included a third pressure transducerthat measures the pressure of the expresser fluid which is an indirectmeasure of the pressure on the red blood cells. The controller adjuststhe expresser pump speed to assure that pressure is within acceptedlimits and cells are protected from damage. If the pressure is too low,the pump rate is increased to speed up the expression cycle. If thepressure is too high, the pump is slowed down to protect the cells fromexcessive pressure. This also protects the seal from excessive pressureas well.

[0038] Optical sensor 58 sensor monitors the color and the turbidity ofthe transferred fluids. Specifically, optical sensor 58 also monitorsthe supernatant expressed from the centrifuge chamber. When red cellsare detected in the supernatant, the controller responds by stopping theexpresser pump to avoid losing any cells to waste or responds byswitching valves to collect the cells in a separate storage bagdepending on which cycle is being performed.

[0039] The cell processing system can be used, for example, in methodsof enzymatically converting blood type or inactivating pathogens.Certain methods of enzymatically converting blood type are set forth inU.S. Pat. Nos. 4,330,619, 4,427,777 and 4,609,627 by Goldstein.

[0040] Processing module 60 includes a “rotating seal” that is a sealcreated between moving and stationary components of the centrifugalelement. The seal acts as a barrier between the interior portion of thesystem in which processing occurs, which is desirably maintained asmicrobe-free as possible, and a nonsterile environment which, at leastduring a portion of the operation of the system, is in communicationwith the environment external to the system. The rotating seal alsoprevents the dispersal of microbes (e.g. viruses) which may exist in acell sample into the external environment.

[0041] The rotating seal comprises an upper element and a lower element,wherein one element rotates during at least a portion of the operationof the cell processing system. The rotating seal surrounds an axialopening through which cells and/or cell elements and processingmaterials are intended to pass during processing.

[0042]FIG. 4 is a cross-section view of a centrifuge bucket and chuckwhich depicts the rotating seal apparatus seated in the chuck.Protruding from the top of the centrifuge bucket are the first port 632,the header shield top 660 and the header shield bottom 650. The rotatingseal apparatus is mounted to the chuck by mounts 686 protruding from thebase 680. The mounts mate with opposing projections fixed to the chuck,thereby transmitting the rotating force of the chuck to the lower partsof the rotating seal apparatus and the processing container to which thebase 680 is mounted.

[0043]FIG. 5 depicts an assembled rotating seal apparatus. The headershield assembly is comprised of the shield top 660, the shield bottom650 and the shield clamp 670. The shield clamp includes an inwardlydirected flange 672 which overlaps an oppositely directed flange on theshield bottom. In alternative embodiments, the shield clamp can have asmaller diameter than the shield bottom, and have an outwardly directedflange to overlap an inwardly directed flange of the shield bottom. Theshield clamp is mounted on the base 680, which in turn is mounted on aprocessing container. As depicted in FIG. 6, the base 680 includes aflange 682 which includes a outwardly directed protrusion 684. When theshield clamp is mounted on the base, the protrusion 684 fits into theindentation 674 on the inside surface of the shield clamp, therebyholding the header shield assembly together and preloading the spring640 to create contact between the sealing surfaces. Ports 632, 634 and636 are included as inlets and outlets for materials passing through therotating seal apparatus to a processing container and for providingmaterials to internal portions of the rotating seal apparatus. These aredescribed in greater detail below.

[0044] Referring to FIGS. 6-9, the rotating seal comprises an uppersealing member 610 and a lower sealing member 620. As shown in FIG. 6,when biased together, the contact of the sealing members creates aplurality of annular seals. A first seal 700 is formed between sealingsurfaces 612 and 622, and a second seal 702 is formed between sealingsurfaces 613 and 622. As shown in FIGS. 6, 7, and 9, the sealing face ofthe upper sealing member 610 is formed into two sealing surfaces 612 and613 as lands surrounding a groove 618. The groove forms the upperboundaries of an annular space 710 between the concentric seals 700,702. The groove can be cut from or molded into the upper sealing memberas desired.

[0045] In the embodiment depicted in FIGS. 6-9, the sealing face of thelower sealing member 620 is not formed into lands and grooves; rather,the sealing surface 622 forms the plurality of concentric seals incombination with the sealing surfaces 612 and 613, and forms the annularspace in combination with the groove 618. In alternative configurationsof the rotating seal, the lower sealing member can include thetopography of lands and grooves and the upper sealing member can beplanar. In still other embodiments, both the upper and the lower sealingmembers can include lands and grooves. The sealing surfaces preferablyare planar, although other geometries also can be used provided that aclose fit can be achieved between stationary and rotating members of therotating seal.

[0046] The upper and lower sealing members 610, 620 also each defineaxial openings 619 and 629, respectively. Upon assembly of the sealingmembers in axial alignment, the axial openings, the first seal, theannular space, and the second seal are positioned concentricallyrelative to each other

[0047] The annular space 710 can be in communication with the externalenvironment, and preferably is in gaseous communication through thechannel 616. The channel can be formed in either of both of the sealingmembers 610, 620. In preferred embodiments the annular space 710constitutes a sterile chamber. Further seals, separated by additionalannular spaces, may also be included in the rotating seal apparatus.

[0048] The rotating seal apparatus depicted in FIGS. 5-9 also includes abody 630 having ports 632, 634 and 636 which serve as inlets and/oroutlets for material passing into and out of a processing container towhich the rotating seal apparatus is mounted. The first port 632traverses the axial opening of the rotating seal apparatus, terminatingat plug 690. The first port preferably serves as an inlet into theprocessing container for cells which are to be processed. The first portadditionally serves as the outlet for processed cell following theexecution of processing steps. The first port can be connected to anumber of tubes, fluid handling manifolds, valves etc. as will be knownto one of ordinary skill in the art.

[0049] The fluid port 636 is in fluid communication with the annularspace 638 bounded by the exterior surface of the first port and thewalls of the axial openings 619, 629, 689, 699 of the upper sealingmember 610, lower sealing member 620, base 680 and plug 690. The fluidport 636 connects to the annular space below. In certain embodiments,the fluid port 636 and annular space 638 are used for passage ofprocessing materials such as wash solutions, buffers, enzymes and thelike into the processing container. The fluid port 636 and annular space638 also are used for passage of waste materials out of the processingcontainer. This outlet function also serves a temperature regulationfunction. As the sealing members of the rotating seal apparatus turnagainst each other, local frictional heating of the rotating sealapparatus above room temperature occurs. Passage of waste materials,which are at temperatures at or below room temperature, out of theprocessing container through the annular space 638 and fluid port 636contact the first port 632 and thereby lower the temperature of thefirst port. The cooled first port does not heat cells as an uncooledport would upon passage of processed cells out of the processingcontainer through the first port. As with the first port, the fluid portcan be connected to a number of tubes, fluid handling manifolds, valvesetc. as will be known to one of ordinary skill in the art.

[0050] The gas port 634 is in gaseous communication with the annularspace 710 between the concentrically spaced seals 700, 702. The gas portpreferably serves as the inlet for providing sterile air (or other gas)to pressurize the annular space 710. The gas port can be connected to anumber of tubes, filters, valves etc. for providing a sterile supply ofgas as will be known to one of ordinary skill in the art.

[0051] The base 680 and plug 690 fit together as depicted in FIG. 6. Asingle unitary base/plug combination also could be used as desired. Thebase 680 serves both as a mount for the lower seal member 620 and as amount for the shield clamp 670 by means of the flange 682 and protrusion684. The base is mounted on the processing container to provide fluidcommunication of the first port 632 and the fluid port 636 with theinterior of the processing container. A plurality of mounts 686 can passthrough sealed portions of the processing container can be mounted onthe chuck of a centrifuge to communicate rotation of the centrifugechuck to the base, processing container and lower seal member of therotating seal apparatus. Other means of securing the rotating sealapparatus and processing container to the centrifuge for providingrotation to the processing container are well known to one of ordinaryskill in the art.

[0052] The spring 640 is depicted in FIGS. 6-9, and comprises a hollowgenerally cylindrical-shaped elastic member having bowed sides. Thespring is disposed between the header shield top 660 and the body 630.As depicted, the spring is provided with flanges 642, 644 at its upperand lower ends. The lower flange 644 fits into an annular recess 631formed in the body. The top flange 642 fits against the header shieldtop. Upon assembly of the rotating seal apparatus by snapping the headershield clamp against the base, the spring is deflected from a firstposition to a second position which provides a “pre-load” of contactforces to the seal members. When the rotating seal apparatus is enclosedin a centrifuge, the spring can be deflected to a third position ofgreater deflection which provides an increased contact force to the sealmembers, thereby creating an enhanced seal.

[0053] In contrast to helical springs, the cylindrical spring of theinvention provides a constant biasing force over a wide range ofcompression. The spring has a height h which describes the axis ofdeflection or compression, a width w which describes the diameter of thespring in nondeflected or deflected positions, an thickness t and an arca. The height, when the spring compressed from the first position, isreduced from h₁ to h₂. Similarly, the spring width is increased oncompression from w₁ to w₂. The spring provides constant biasing forceover a Δh of at least 10%, preferably at least 20%, more preferably atleast 30% and most preferably at least 50%. Further, the spring providesconstant biasing force over a Δw of at least 1%, preferably at least 2%,more preferably at least 5% and most preferably at least 10%. The rangeof compression over which the biasing force is constant also can bedescribed by the ratio of Δh:Δw, wherein the spring experiences arelatively large Δw for a corresponding Δh. The thickness t of thespring should not be too great as to hinder the bowing of the cylindersides on compression of the spring. A range of thicknesses and arcs willbe useful to provide proper bowing; these ranges can easily bedetermined by one of ordinary skill in the art with no more than routineexperimentation, and may depend on the particular elastomeric materialchosen for manufacture of the spring. The appropriate thickness and arcscan be expressed in terms of ratios of h:t and h:a, when h, t, and a aremeasured in deflected or nondeflected positions.

[0054] The rotating seal apparatus of the invention may be validated as“closed” devices, and thereby produce product with longer shelf lifethan prior art rotating seal devices. A second annular seal providedcircumferentially around the first or inner seal provides furtherassurance of seal integrity. To still further promote the sterility ofthe interior of the seal and processing container, the annular space 710can be filled with sterile air and, further, a pressure differential maybe created such that the sterile air in the annular space is at apressure higher than the pressure in the surrounding chamber formed bythe header shield. Therefore, the flow pattern of the hydrodynamic filmmay be directed away from the sterile interior and toward the spacesexterior to the rotating seals. Further, the chamber formed by theheader shield may be provided with a steady supply of sterile air at apressure lower than that in the annular space 710 but higher thanambient pressure. This “double redundancy” of the two surroundingsterile chambers at graduating pressures is theoretically analogous tothat used in the design of clean rooms for sterile filing ofpharmaceuticals.

[0055] The annular space 710 can be filled with a gas or liquid;preferably, the gas or liquid is substantially sterile. The enclosedspace thereby creates a barrier to microbes or other particulatematerials passing into or out of the interior of the cell processingsystem. The gas or liquid may be introduced into the enclosed space viaa channel which passes through or between the upper and lower elements.For example, referring to FIG. 6, air can be pumped through a 0.2 micronfilter to assure sterility, and then be pumped through the gas port 634to the channel 616 and into the annular space 710. Optionally theannular space 638 formed between the inner seal 700 and the first port632 can be pressurized, for example when the annular space 638 is notconveying reagents into the processing container 604 or waste liquidsout of the processing container. Preferably the annular space 710 ispressurized with sterile air at pressure slightly above atmosphericpressure. For example, it has been determined that an air pressure ofapproximately 0.25 PSIG suffices to provide a pressurized environment inthe annular space to enhance the sealing function of the sealingmembers. Other pressures and gases can also be employed in similarfashion as will be evident to one of ordinary skill in the art. Inalternative embodiments, the annular space is pressurized relative tothe exterior and interior of the rotating seal apparatus by evacuatingthe exterior and/or interior (e.g. the space inside the header shieldand/or the annular space 638, respectively) by means of a vacuum pump orother device which creates a pressure differential.

[0056] In certain embodiments of the invention, the sterile air may beprovided from a pressurized tank that uses a precise pressure regulatingvalve to reduce the tank pressure to a level that is slightly positiverelative to ambient pressures (e.g. 0.25 PSIG). A computer softwarecontrolled “watchdog circuit” may be placed in communication with theannular space 710 to indicate, in a detectable manner, if and whenundesirable pressure levels in the interior of the cell processingsystem occur. Furthermore, alterations in pressure in the annular space,detectable by a pressure monitor, may alert a system operator that oneof the sealing elements has been breached and/or the barrier function ofthe annular space has been disrupted.

[0057] A second redundant sterile chamber can be created by the headershield assembly (shield top, shield bottom and shield clamp) thatsurrounds both the first and the second seal members. Sterile air may besupplied to this chamber at a pressure that is less than that of theannular space between the seals but greater than the surrounding ambientcondition. The flow of air is from areas of higher pressure to areas oflower pressure. Therefore, the flow of sterile air may be directed fromthe inside of the seal and in an outward direction. Potential microbialcontamination may thus be swept away from the sterile interior of theseal by this flow vector.

[0058] A serpentine seal 676 is formed between the close tolerance ofthe opposing flanges 672, 652 of the shield bottom and shield clamp. Theserpentine seal may create shear forces between the surfaces of theflanges which prevent particulate material from the outside the shieldfrom entering the shield and thus the seal assembly. In general, theserpentine seal acts as a physical barrier, if not a seal, tocontaminants external to the rotating seal apparatus.

[0059] In additional embodiments, the rotating seal apparatus can beformed of two concentric lip seals or two concentric barrel seals.Between lip seals or barrel seals is an annular space analogous toannular space 710. The annular space is in communication with a sourceof gas or liquid (e.g., sterile pressurized air). Additional seal typeswill be known to one of ordinary skill in the art.

[0060] In operation, the rotating seal apparatus is provided as apreassembled device, properly preloaded by spring biasing force tocreate seals between the upper and lower sealing members. The rotatingseal apparatus is placed in a cell processing system centrifugal device,for example by mounting it on a centrifuge chuck by the mounts 686.Closing the centrifugal device causes the compression of the spring to athird position which forces the seals into closer contact than thepreload contact and maintains the close contact during rotation. Theports 632, 634 and 636 are joined to an appropriate set of tubes,optionally via connectors, to provide cells, processing materials,sterile air, etc. to the rotating seal apparatus and processingcontainer. Upon rotation of the centrifugal device, the upper sealmember, body, header shield top and bottom remain stationary and thelower seal member, base (and attached processing container), and headershield clamp rotate while the integrity of the seals are maintained.

[0061] The sealing surfaces of the upper and lower sealing members canbe formed or fabricated of a variety of materials well known to one ofordinary skill in the art. Suitable materials include ceramics, carbonphenolic, graphite and graphite derivatives, lubricious plasticmaterials such as nylon, delrin, teflon, rulon, bronze and alloysthereof, stainless steel, carbon nitrites, etc. The sealing members canbe manufactured as a single piece or as a separate sealing portions andsupport portions of the sealing member. The sealing members can bemanufactured, for example, by injection molding or other method offabrication, followed by making the sealing surfaces flat (e.g. bygrinding or lapping) and polishing. The sealing members thus treatedhave sealing surfaces which when contacted essentially prevent fluidpassage. Preferred materials include ceramics and carbon phenoliccompounds. In a preferred embodiment, the upper and lower sealingelements are formed of ceramic which is lapped and polished.

[0062] Other parts of the apparatus are constructed of various polymericmaterials which preferably are FDA-approved for medical devices. Theheader shield top 660, the header shield bottom 650 and the headershield clamp 670 are preferably constructed of high impact polystyrene(HIPS), although any rigid plastic known to one of ordinary skill in theart which has some elastomeric properties can be used. The body 630 andthe base 680 are preferably constructed of polycarbonate which providesgood strength and stability. Other like materials can also be used.

[0063] The spring 640 is constructed of an elastomeric material, andpreferably is constructed of a medium durometer silicon material such asthermoset silicon or liquid injection molding silicon. One also coulduse various rubber materials for the spring, preferably materials whichare FDA approved for medical devices.

[0064] The present invention may be used in a variety of cell and cellelement processing procedures, including collection and/or washing orred blood cells, platelets, lymphocytes, granulocytes, monocytes, andstem cells (e.g., from peripheral blood, bone marrow, or cord blood), aswell as other methods such as viral inactivation. In preferredembodiments, the cell processing system may be used in methods ofenzymatically converting blood type. Methods of converting blood typeare, for example, set forth in U.S. Pat. Nos. 4,330,619 and 4,609,627 byGoldstein. Other uses for the rotating seal portion of the apparatuswill be known to one of ordinary skill in the art.

EQUIVALENTS

[0065] Those skilled in the art will recognize, or be able to ascertainusing no more than routine experimentation, many equivalents to thespecific embodiments of the invention described herein. Such equivalentsare intended to be encompassed by the following claims.

[0066] All references disclosed herein are incorporated by reference intheir entirety.

In the claims:
 26. Apparatus for selectively expressing one or moreselected fluid materials out of a fluid container, wherein each of theselected fluid materials has a selected density and wherein the fluidcontainer comprises a round enclosure having a flexible wall and an exitport sealably communicating with the fluid container for enabling theselected fluid materials contained therein to be expressed out of thefluid container through the exit port, the apparatus comprising: acentrifuge rotor having a round centrifuge chamber of selected volume,the centrifuge rotor being controllably rotatable around a central axisby a motor mechanism; a round expandable enclosure disposed within thecentrifuge chamber having a rotation axis 10 coincident with the centralrotation axis and a flexible wall, the fluid container having a rotationaxis and being coaxially receivable within the centrifuge chamber, theexpandable enclosure being sealably connected to a source of anexpressor fluid which has a density selected to be greater than thedensity of each of the selected one or more fluid materials disposed inthe fluid container; a pump for controllably pumping a selected volumeof the expressor fluid into and out of the expandable enclosure whereinthe fluid container is receivable within the centrifuge chamber; aretaining mechanism for holding the fluid container within thecentrifuge chamber in a coaxial position wherein the flexible wall ofthe fluid container is in contact with the flexible wall of theexpandable enclosure.
 27. The apparatus of claim 26 wherein theexpandable enclosure comprises a flexible membrane sealably attached toa surface of the rotor such that the centrifuge chamber is divided intoa first chamber for receiving the fluid container and a second fluidsealed chamber for receiving the expressor fluid.
 28. The apparatus ofclaim 26 wherein the flexible wall of the expandable enclosure comprisesan elastomeric sheet material.
 29. The apparatus of claim 26 furthercomprising a heater mechanism having a control mechanism for selectivelycontrolling the temperature of the expresser fluid.
 30. The apparatus ofclaim 26 wherein the fluid container has a first radius and the secondfluid sealed chamber has a second radius which is at least equal to thefirst radius of the fluid container, wherein the expresser fluid pumpedinto the second fluid sealed chamber travels to a circumferentialposition within the second fluid sealed chamber which is more radiallyoutward from the central axis than a circumferential position to whichthe one or more selected fluid materials in the fluid container travelwhen the rotor is drivably rotated around the central axis. 31.Apparatus for selectively expressing one or more selected fluidmaterials out of a fluid container, wherein each of the selected fluidmaterials has a selected density and wherein the fluid containercomprises a round enclosure having a rotation axis, a flexible wall andan exit port sealably communicating with the container for enabling theselected fluid materials contained therein to be expressed out of thecontainer through the exit port, the apparatus comprising: a centrifugerotor having a round centrifuge chamber, the centrifuge rotor beingcontrollably rotatable around a central axis by a motor mechanism; aflexible membrane sealably attached to a surface of the rotor such thatthe centrifuge chamber is divided into a first chamber for receiving thefluid container coaxially with the central rotation axis and a secondround fluid sealed chamber having a rotation axis coincident with thecentral axis for receiving an expressor fluid, wherein the expressorfluid has a density selected to be greater than the density of each ofthe selected one or more fluid materials disposed in the container; apump for controllably pumping a selected volume of the expressor fluidinto and out of the second fluid sealed centrifuge chamber; a retainingmechanism for holding the container within the first chamber in aposition wherein the flexible wall of the container is in contact withan outside surface of the flexible membrane.
 32. The apparatus of claim31 wherein the flexible membrane comprises an elastomeric sheetmaterial.
 33. The apparatus of claim 31 further comprising a heatermechanism having a control mechanism for selectively controlling thetemperature of the expresser fluid.
 34. The apparatus of claim 31wherein the fluid container has a first radius and the second fluidsealed chamber has a second radius which is at least equal to the firstradius of the fluid container, wherein the expresser fluid pumped intothe second fluid sealed chamber travels to a circumferential positionwithin the second fluid sealed chamber which is more radially outwardfrom the central axis than a circumferential position to which the oneor more selected fluid materials in the fluid container travel when therotor is drivably rotated around the central axis.
 35. In a centrifugeapparatus comprising a rotor having a centrifuge chamber which iscontrollably rotatable around a central axis, a method for expressingone or more selected fluid materials each having a selected density outof a fluid container which contains the selected fluid materials whereinthe fluid container comprises a round enclosure having a radius, arotation axis, a flexible wall and an exit port sealably communicatingwith the fluid container for enabling the selected fluid materialscontained therein to be expressed out of the fluid container through theexit port, the method comprising: forming a round expandable enclosurewithin the centrifuge chamber wherein the expandable enclosure has aflexible wall, a radius and a rotation axis coincident with the centralaxis of the rotor; mounting the fluid container coaxially within thecentrifuge chamber such that the flexible wall of the fluid containerfaces the flexible wall of the expandable enclosure; selecting anexpresser fluid having a density greater than the density of each of theselected fluid materials; pumping the selected expressor fluid into theexpandable enclosure in an amount sufficient to expand the expandableenclosure such that the flexible wall of the expandable enclosurecontacts the flexible wall of the fluid container; and, drivablyrotating the rotor around the central axis before, during or after thestep of pumping.
 36. The method of claim 35 wherein the radius of theexpandable enclosure is selected to be at least equal to the radius ofthe fluid container.
 37. Apparatus for selectively expressing one ormore selected fluid materials out of a fluid container, wherein each ofthe selected fluid materials has a selected density and wherein thefluid container comprises a round enclosure having a flexible wall andan exit port sealably communicating with the fluid container forenabling the selected fluid materials contained therein to be expressedout of the fluid container through the exit port, the apparatuscomprising: a separation housing having a round chamber of selectedvolume, the housing having a central axis; a round expandable enclosuredisposed within the round chamber having an axis coincident with thecentral axis of the separation chamber and a flexible wall, the fluidcontainer having an axis and being coaxially receivable within the roundchamber, the expandable enclosure being sealably connected to a sourceof an expressor fluid which has a density selected to be greater thanthe density of each of the selected one or more fluid materials disposedin the fluid container; a pump for controllably pumping a selectedvolume of the expresser fluid into and out of the expandable enclosurewherein the fluid container is receivable within the round chamber; aretaining mechanism for holding the fluid container within the roundchamber in a coaxial position wherein the flexible wall of the fluidcontainer is in contact with the flexible wall of the expandableenclosure.
 38. The apparatus of claim 37 wherein the expandableenclosure comprises a flexible membrane sealably attached to a surfaceof the separation housing such that the round chamber is divided into afirst chamber for receiving the fluid container and a second fluidsealed chamber for receiving the expressor fluid.
 39. The apparatus ofclaim 37 wherein the flexible wall of the expandable enclosure comprisesan elastomeric sheet material.
 40. The apparatus of claim 37 wherein thefluid container has a first radius and the expandable enclosure has asecond radius which is at least equal to the first radius of the fluidcontainer.
 41. The apparatus of claim 37 further comprising a heatermechanism having a control mechanism for selectively controlling thetemperature of the expressor fluid.
 42. Apparatus for selectivelyexpressing one or more selected fluid materials out of a fluidcontainer, wherein each of the selected fluid materials has a selecteddensity and wherein the fluid container comprises a round enclosurehaving a flexible wall and an exit port sealably communicating with thefluid container for enabling the selected fluid materials containedtherein to be expressed out of the fluid container through the exitport, the apparatus comprising: a centrifuge rotor having a roundcentrifuge chamber of selected volume, the centrifuge rotor beingcontrollably rotatable around a central axis by a motor mechanism; around expandable enclosure disposed within the centrifuge chamber havinga rotation axis coincident with the central rotation axis arid aflexible wall, the fluid container having a rotation axis and beingcoaxially receivable within the centrifuge chamber, the expandableenclosure being sealably connected to a source of an expressor fluid; apump for controllably pumping a selected volume of the expressor fluidinto and out of the expandable enclosure; wherein the fluid containerhas a flexible wall and is receivable within the centrifuge chamber suchthat the flexible wall of the fluid container faces the flexible wall ofthe expandable enclosure; a mechanism for filling the fluid containerwith any preselected variable volume of the one or more selected fluidmaterials which is less than the selected volume of the centrifugechamber; a retaining mechanism for holding the fluid containercompletely within the centrifuge chamber upon expansion of theexpandable enclosure.
 43. The apparatus of claim 42 wherein theexpandable enclosure comprises a flexible membrane sealably attached toa surface of the rotor such that the centrifuge chamber is divided intoa first chamber for receiving the fluid container and a second fluidsealed chamber for receiving the expressor fluid.
 44. The apparatus ofclaim 42 wherein the flexible wall of the expandable enclosure comprisesan elastomeric sheet material.
 45. The apparatus of claim 42 wherein theexpressor fluid has a density selected to be greater than the density ofeach of the selected one or more fluid materials disposed in the fluidcontainer;
 46. The apparatus of claim 42 wherein the fluid container hasa first radius and the expandable enclosure has a second radius which isat least equal to the first radius of the fluid container, wherein theexpressor fluid pumped into the expandable enclosure travels to acircumferential position within the expandable enclosure which is moreradially outward from the central axis than a circumferential positionto which the one or more selected fluid materials in the fluid containertravel when the rotor is drivably rotated around the central axis. 47.The apparatus of claim 42 further comprising a heater mechanism having acontrol mechanism for selectively controlling the temperature of theexpressor fluid.
 48. Apparatus for selectively expressing one or moreselected fluid materials out of a fluid container, wherein each of theselected fluid materials has a selected density and wherein the fluidcontainer comprises a round enclosure having a rotation axis, a flexiblewall and an exit port sealably communicating with the container forenabling the selected fluid materials contained therein to be expressedout of the container through the exit port, the apparatus comprising: acentrifuge rotor having a round centrifuge chamber of selected volume,the centrifuge rotor being controllably rotatable around a central axisby a motor mechanism; a flexible membrane sealably attached to a surfaceof the rotor such that the centrifuge chamber is divided into a firstchamber for receiving the fluid container coaxially with the centralrotation axis and a second round fluid sealed chamber having a rotationaxis coincident with the central axis for receiving an expressor fluid;a pump for controllably pumping a selected volume of the expressor fluidinto and out of the second fluid sealed centrifuge chamber; wherein thefluid container has a flexible wall and is receivable within thecentrifuge chamber such that the flexible wall of the fluid containerfaces the flexible wall of the expandable enclosure; a mechanism forfilling the fluid container with any preselected variable volume of theone more selected fluid materials which is less than the selected volumeof the centrifuge chamber; a retaining mechanism for holding the fluidcontainer completely within the centrifuge chamber upon expansion of theexpandable enclosure.
 49. The apparatus of claim 48 wherein the flexiblemembrane comprises an elastomeric sheet material.
 50. The apparatus ofclaim 48 wherein the expressor fluid has a density selected to begreater than the density of each of the selected one or more fluidmaterials disposed in the fluid container;
 51. The apparatus of claim 48wherein the fluid container has a first radius and the second fluidsealed chamber has a second radius which is at least equal to the firstradius of the fluid container, wherein the expressor fluid pumped intothe second fluid sealed chamber travels to a circumferential positionwithin the second fluid sealed chamber which is more radially outwardfrom the central axis than a circumferential position to which the oneor more selected fluid materials in the fluid container travel when therotor is drivably rotated around the central axis.
 52. The apparatus ofclaim 48 further comprising a heater mechanism having a controlmechanism for selectively controlling the temperature of the expressorfluid.
 53. In a centrifuge apparatus comprising a rotor having acentrifuge chamber of a selected volume which is controllably rotatablearound a central axis, a method for expressing one or more selectedfluid materials each having a selected density out of a fluid containerwhich contains the selected fluid materials wherein the fluid containercomprises a round enclosure having a rotation axis, a flexible wall andan exit port sealably communicating with the fluid container forenabling the selected fluid materials contained therein to be expressedout of the fluid container through the exit port, the method comprising:forming a round expandable enclosure within the centrifuge chamberwherein the expandable enclosure has a flexible wall and a rotation axiscoincident with the central axis of the rotor; mounting the fluidcontainer coaxially within the centrifuge chamber such that the flexiblewall of the fluid container faces the flexible wall of the expandableenclosure; filling the fluid container with any preselected variablevolume of the one on more of the selected fluid materials which is lessthan the selected volume of the centrifuge chamber before, during orafter the step of mounting; pumping a selected expresser fluid into theexpandable enclosure in an amount sufficient to expand the expandableenclosure such that the flexible wall of the expandable enclosurecontacts the flexible wall of the fluid container; holding the fluidcontainer completely within the centrifuge chamber during the steppumping and, drivably rotating the rotor around the central axis beforeor during the step of pumping.
 54. The method of claim 53 wherein thestep of pumping includes preselecting the expressor fluid to have adensity greater than the density of each of the selected fluidmaterials.
 55. The method of claim 53 further comprising placing theexpressor fluid at one or more selected temperatures prior to or duringthe step of pumping.
 56. In a centrifuge apparatus comprising a rotorhaving a centrifuge chamber of a selected volume which is controllablyrotatable around a central axis, a method for consistently processing aselected biological cell material between separate processing cycles inthe centrifuge apparatus, the method comprising: selecting a fluidmaterial having a predetermined composition for treatment of theselected biological cell material; forming a round expandable enclosurewithin the centrifuge chamber wherein the expandable enclosure has aflexible wall and a rotation axis coincident with the central axis ofthe rotor; mounting a round fluid container having rotation axis, aflexible wall and an exit port sealably communicating with the fluidcontainer coaxially within the centrifuge chamber such that the flexiblewall of the fluid container faces the flexible wall of the expandableenclosure; filling the fluid container with a volume of the selectedbiological cells and a volume of the selected fluid material in apredetermined ratio before, during or after the step of mounting;pumping a selected expressor fluid into the expandable enclosure in anamount sufficient to expand the expandable enclosure such that theflexible wall of the expandable enclosure contacts the flexible wall ofthe fluid container; holding the fluid container completely within thecentrifuge chamber during the step pumping; drivably rotating the rotoraround the central axis before or during the step of pumping; and,repeating the steps of mounting, filling, pumping, holding and drivablyrotating at least once.
 57. The method of claim 56 wherein the step ofpumping includes preselecting the expresser fluid to have a densitygreater than the density of the selected biological cell material andthe selected fluid material.
 58. The method of claim 56 furthercomprising placing the expresser fluid at one or more selectedtemperatures prior to or during the step of pumping.
 59. Apparatus forselectively expressing one or more selected fluid materials out of afluid container, wherein each of the selected fluid materials has aselected density and wherein the fluid container comprises a roundenclosure having a flexible wall and an exit port sealably communicatingwith the fluid container for enabling the selected fluid materialscontained therein to be expressed out of the fluid container through theexit port, the apparatus comprising: a centrifuge rotor having a roundcentrifuge chamber of selected volume, the centrifuge rotor beingcontrollably rotatable around a central axis by a motor mechanism; around expandable enclosure disposed within the centrifuge chamber havinga rotation axis coincident with the central rotation axis and a flexiblewall, the fluid container having a rotation axis and being coaxiallyreceivable within the centrifuge chamber, the expandable enclosure beingsealably connected to a source of an expresser fluid; a pump forcontrollably pumping a selected volume of the expressor fluid into andout of the expandable enclosure wherein the fluid container isreceivable within the centrifuge chamber; a heater mechanism having acontrol mechanism for selectively controlling the temperature of theexpressor fluid; a retaining mechanism for holding the fluid containerwithin the first chamber in a coaxial position wherein the flexible wallof the fluid container is in contact with the flexible wall of the fluidcontainer.
 60. The apparatus of claim 59 wherein the control mechanismincludes a program for automatically controlling the temperature of theexpresser fluid.
 61. The apparatus of claim 59 wherein the expandableenclosure comprises a flexible membrane sealably attached to a surfaceof the rotor such that the centrifuge chamber is divided into a firstchamber for receiving the fluid container and a second fluid sealedchamber for receiving the expresser fluid.
 62. The apparatus of claim 59wherein the flexible wall of the expandable enclosure comprises anelastomeric sheet material.
 63. The apparatus of claim 59 wherein theexpressor fluid has a density selected to be greater than the density ofeach of the selected one or more fluid materials disposed in thecontainer.
 64. The apparatus of claim 59 wherein the fluid container hasa first radius and the second fluid sealed chamber has a second radiuswhich is at least equal to the first radius of the fluid container,wherein the expressor fluid pumped into the second fluid sealed chambertravels to a circumferential position within the second fluid sealedchamber which is more radially outward from the central axis than acircumferential position to which the one or more selected fluidmaterials in the fluid container travel when the rotor is drivablyrotated around the central axis.
 65. Apparatus for selectivelyexpressing one or more selected fluid materials out of a fluidcontainer, wherein each of the selected fluid materials has a selecteddensity and wherein the fluid container comprises a round enclosurehaving a rotation axis, a flexible wall and an exit port sealablycommunicating with the container for enabling the selected fluidmaterials contained therein to be expressed out of the container throughthe exit port, the apparatus comprising: a centrifuge rotor having around centrifuge chamber, the centrifuge rotor being controllablyrotatable around a central axis by a motor mechanism; a flexiblemembrane sealably attached to a surface of the rotor such that thecentrifuge chamber is divided into a first chamber for receiving thefluid container coaxially with the central rotation axis and a secondround fluid sealed chamber having a rotation axis coincident with thecentral axis for receiving an expressor fluid; a pump for controllablypumping a selected volume of the expresser fluid into and out of thesecond fluid sealed centrifuge chamber; a heater mechanism having acontrol mechanism for selectively controlling the temperature of theexpressor fluid; a retaining mechanism for holding the container withinthe first chamber in a position wherein the flexible wall of thecontainer is in contact with an outside surface of the flexiblemembrane.
 66. The apparatus of claim 65 wherein the control mechanismincludes a program for automatically controlling the temperature of theexpressor fluid.
 67. The apparatus of claim 65 wherein the flexiblemembrane comprises an elastomeric sheet material.
 68. The apparatus ofclaim 65 wherein the expressor fluid has a density selected to begreater than the density of each of the selected one or more fluidmaterials disposed in the container.
 69. The apparatus of claim 65wherein the fluid container has a first radius and the second fluidsealed chamber has a second radius which is at least equal to the firstradius of the fluid container, wherein the expresser fluid pumped intothe second fluid sealed chamber travels to a circumferential positionwithin the second fluid sealed chamber which is more radially outwardfrom the central axis than a circumferential position to which the oneor more selected fluid materials in the fluid container travel when therotor is drivably rotated around the central axis.
 70. In a centrifugeapparatus comprising a rotor having a centrifuge chamber which iscontrollably rotatable around a central axis, a method for expressingone or more selected fluid materials each having a selected density outof a fluid container which contains the selected fluid materials whereinthe fluid container comprises a round enclosure having a radius, arotation axis, a flexible wall and an exit port sealably communicatingwith the fluid container for enabling the selected fluid materialscontained therein to be expressed out of the fluid container through theexit port, the method comprising: forming a round expandable enclosurewithin the centrifuge chamber wherein the expandable enclosure has aflexible wall, a radius and a rotation axis coincident with the centralaxis of the rotor; mounting the fluid container coaxially within thecentrifuge chamber such that the flexible wall of the fluid containerfaces the flexible wall of the expandable enclosure; selecting anexpressor fluid having a density greater than the density of each of theselected fluid materials; pumping the selected expresser fluid into theexpandable enclosure in an amount sufficient to expand the expandableenclosure such that the flexible wall of the expandable enclosurecontacts the flexible wall of the fluid container; and, drivablyrotating the rotor around the central axis before, during or after thestep of pumping.
 71. The method of claim 70 further comprising placingthe expressor fluid at one or more selected temperatures prior to orduring the step of pumping.
 72. The method of claim 70 wherein theradius of the expandable enclosure is selected to be at least equal tothe radius of the fluid container.